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Japanese Beetle Adult Feeding and Host Preference

July 28, 1999

Japanese beetle adults are a major problem in landscapes because they feed on a wide variety of annuals, perennials, trees, shrubs, and vines. However, certain plants are more susceptible to their attack. These plants are listed in Table 1. In contrast, many plants are less susceptible to attack by Japanese beetle adults. These plants are listed in Table 2.

Research has demonstrated that natural sugar content and presence of odoriferous substances are important factors in determining the susceptibility of plants to attack by Japanese beetle adults. A study showed that plants with higher amounts of the reducing sugar dextrose suffered greater damage from beetle adults than plants with lower amounts of dextrose.

Table 1. Ornamental plants highly susceptible to feeding by Japanese beetle adults.
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Japanese maple Norway maple
Gray birch Horsechestnut
Black walnut Sassafras
American elm Althea
London planetree Rose
Black cherry Crab apple
American mountain ash Lombardy poplar
Pussy willow American linden
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Table 2. Ornamental plants less susceptible to feeding by Japanese beetle adults.
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Red maple Silver maple
American holly Boxwood
Snowberry Winged euonymus
Flowering dogwood White cedar
Yellow poplar Saucer magnolia
White ash Green ash
Lilac Norway spruce
Scotch pine Douglas fir
Canadian hemlock Mock orange
Hydrangea Yew
Forsythia
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Odoriferous chemicals have also been shown to play a role in the attractiveness of certain plants to Japanese beetles. Ginkgo biloba, which is not usually attacked by Japanese beetle adults, may lack certain odoriferous chemicals that are attractive to them. However, many susceptible plants such as rose and apple contain the substance geraniol, which is highly attractive to Japanese beetle adults. It should be noted that when Japanese beetle adult populations are heavy and food is a limiting factor, plants that are less susceptible to Japanese beetle adult feeding might be fed upon.


Author: Raymond Cloyd

 

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